1. Field of the Invention
The present invention generally relates to a digital device, and more particularly to a digital device with image means that is portable in an outdoor area and can provide information in an image form.
2. Description of the Related Art
With the development of electronic and digital technologies, digital devices are being supplied in various personal, portable forms, such as a navigation system, personal digital assistant (PDA), portable phone, notebook computer, electronic dictionary, Motion Pictures Experts Group (MPEG) Audio Layer 3 (MP3) digital camcorder, camera, and so on. The digital devices are equipped with image means for providing a user with information. The image means can use a liquid crystal display (LCD), plasma display panel (PDP), and so on. The image means can provide various types of image information such as text, still images, motion images, etc.
The perception of a human being undergoes variation in sensitivity, i.e., light-adapted sensitivity, in which luminance, chroma, and so on of an image perceived from the image means are different according to different possible luminance levels in ambient illumination. Luminance refers to the amount of light in a particular area. Chroma, which is short for “chrominance,” includes hue and saturation. Hue is the dominant wavelength of a color. Saturation refers to the amount of black a color contains.
The variation in sensitivity due to light adaptation affords vision of a given image in, for example, a relatively dark, or low chroma, level although the actual optical characteristics of the given image are not configured to be responsive to background illumination from around the image means.
Although recent digital devices are highly integrated to achieve small size, be lightweight, and offer multiple functions, and provide users with the convenience of various information and functions the user, problematically, does not acquire, or incorrectly acquires, information from the image means adjusted for variation in external background illumination.
When, for example, the digital devices are used in an outdoor area, the user may, due to the variation in external background illumination, perceive luminance and chroma of an image differently from the actual luminance and chroma, i.e., that associated with the image without regard to ambient light influences. As a result, the user may perceive, in bright daylight for example, an image provided from the digital device at a darker level than that of ambient background illumination. Accordingly, the desired information is not acquired. In addition, the color human vision perceives may vary with ambient light. This variation is termed flare. When a flare phenomenon occurs due to light reflected from the display screen of the device, image information is not smoothly acquired. More particularly, the user incorrectly perceives an image, from the screen giving rise to the flare phenomenon, in a relatively low chroma state as compared with a normal state.